Stimulating Stem Cells Fights Stroke Damage

In the 22 June 2006 issue of Nature (Vol. 441, No.7096), Ronald McKay and his colleagues show that stimulating a specific signalling pathway in the neural stem cells of rat brain can help the animals recover movement after a simulated stroke. The finding paves the way towards therapies in which doctors can provoke the body's endogenous stem cells to repair damage rather than trying to grow and transplant new cells.

The team shows that activation of a receptor called Notch promotes the survival of neural stem cells in the laboratory and in rat brain by triggering a cascade of cellular events, including a pathway already implicated in cancer. They show that the same pathway is important for survival of human embryonic stem cells. When the researchers starved rats' brains of oxygen and then infused proteins that activate the Notch receptor, this boosted the number of new cells generated and helped avoid the typical loss of movement.

"These data indicate that stem cell expansion in vitro and in vivo, two central goals of regenerative medicine, may be achieved by Notch ligands through a pathway that is fundamental to development and cancer," the authors write.